Sensitive photographic-printing paper.



' UNITED STATES,

Patented May 23, 1905.

ERNEST CHARLES MORGAN, OF RICHMOND, ENGLAND.

SENSITIVE PHOTOGRAPHlC-PRINTING PAPER- SPEGIFIGATION forming part of LettersPatent No. 790,647, dated May 23, 1905.

Application filed December 22, 1904. Serial No. 288,014.

' have invented certain new and useful 1mprovements in Sensitive Photographic-Printlng Papers of the class known as Self-Toning Printing-Out Papers and the Like, of which the following is a specification.

My invention relates to an improvement in sensitized photographic-printing papers, plates, and films, more especially of the class known as self-toning printing-out papers, plates, and films, the invention consisting, essentially, in the employment as vehicle for the light-sensitive salts in the emulsion with which the support (paper, glass,celluloid ,&c. is coated of agar-agar and arrowroot or other suitable starch in substitution for gelatin or collodion. When paper is used as the support, it maybe a pure raw paper or a paper with a baryta-coated surface, such as is in general use for photographic printing-out papers.

For a self-toning printing-out paper, the sensitive emulsion is made as follows: To twenty-four ounces of water add one and onehalf ounces of arrowroot or other suitable starch and boil. In this mixture when cool dissolve sugar, six drains; citric acid, five drams; ammonium chlorid, sixty-four grains; and Rochelle salt, four drams, and mix thoroughly. Add slowly nine drams thirty-six grains of nitrate of silver dissolved in eight,

ounces of water. Next add slowly eleven grains of chlorid of gold dissolved in six ounces of water. 7 Finally, take agar-agar two drams, boiled till dissolved in eighteen ounces of wa-. ter, and add warmto the above mixture.

The paper, glass, celluloid, or other support is first coated with the above-described emulsion in a warm state and is then dried in a dark chamber. The sensitive paperor other material may thereafter be printed by exponegative in the usual manner until a visible image of suflicient strength is obtained.

If a print of a purple-brown tone be required, the print is first washed for about ten minutes in running water and is then fixed and toned in one operation by immersion for immersed for fifteen minutes in a bath containing twenty ounces of chlorid of sodium to one hundred ounces of water.

My reason for usingagar-agar and arrowroot or other suitable starch as a medium in which to carry the light-sensitive salts instead of employing gelatin or collodion, which are the usual vehicles, is that in the case of self-toning papers when gelatin is used as the vehicle the gold saltis not so easily reduced and will not give such satisfactory tones by immersion in hyposulfite-of-soda solutions only, while collodion as a vehicle is more costly.

I claim 1. As a new article of manufactureaphotographic printing out paper, plate or film, comprising a support coated with a layer of a light-sensitive emulsion containing a mixture of light-sensitive salts with agar-agar and starch.

2. As a new article of manufacture, a photographic-printing paper, plate or film,compris ing a support coated with a light-sensitive emulsion containing a gold salt, starch, and

agar-agar.

3. As a new article of manufacture a photographic self-toning printing-out paper, plate or film, comprising a support coated with a layer of a light-sensitive emulsion containing a mixture of light-sensitive salts and chlorid of gold with agar-agar and starch.

4. As a new article of manufacture, a photosure to the action of light under a photographic 1 graphic printing-out paper, plate or film, com 9 prising a support coated with a mixture of citric acid, ammonium chlorid, Rochelle salt, aqueous solutions of starch, sugar, citric acid, nitrate of silver, chlorid of gold, and agar- 10 ammonium chlorid, Rochelle salt, nitrate of agar.

silver and agar-agar.

\ 1 5. As a new article of manufacture, a photo- ERNESL (JHARLEb MORGAN graphic self-toning printing-out paper, plate Witnesses: or film, consistingof a support coated with a H. D. JAMEsoN, mixture of aqueous solutions of starch, sugar, ALFRED NUTTING. 

